1. Confirmation of the spectral excess in DAMIC at SNOLAB with skipper CCDs
- Author
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Aguilar-Arevalo, A, Arnquist, I, Avalos, N, Barak, L, Baxter, D, Bertou, X, Bloch, IM, Botti, AM, Cababie, M, Cancelo, G, Castelló-Mor, N, Cervantes-Vergara, BA, Chavarria, AE, Cortabitarte-Gutiérrez, J, Crisler, M, Cuevas-Zepeda, J, Dastgheibi-Fard, A, De Dominicis, C, Deligny, O, Drlica-Wagner, A, Duarte-Campderros, J, D’Olivo, JC, Essig, R, Estrada, E, Estrada, J, Etzion, E, Favela-Perez, F, Gadola, N, Gaïor, R, Holland, SE, Hossbach, T, Iddir, L, Kilminster, B, Korn, Y, Lantero-Barreda, A, Lawson, I, Lee, S, Letessier-Selvon, A, Loaiza, P, Lopez-Virto, A, Luoma, S, Marrufo-Villalpando, E, McGuire, KJ, Moroni, GF, Munagavalasa, S, Norcini, D, Orly, A, Papadopoulos, G, Paul, S, Perez, SE, Piers, A, Privitera, P, Robmann, P, Rodrigues, D, Saffold, NA, Scorza, S, Settimo, M, Singal, A, Smida, R, Sofo-Haro, M, Stefanazzi, L, Stifter, K, Tiffenberg, J, Traina, M, Uemura, S, Vila, I, Vilar, R, Volansky, T, Warot, G, Yajur, R, Yu, T-T, and Zopounidis, J-P
- Subjects
Nuclear and Plasma Physics ,Physical Sciences - Abstract
We present results from a 3.25 kg-day target exposure of two silicon charge-coupled devices (CCDs), each with 24 megapixels and skipper readout, deployed in the DAMIC setup at SNOLAB. With a reduction in pixel readout noise of a factor of 10 relative to the previous detector, we investigate the excess population of low-energy events in the CCD bulk previously observed above expected backgrounds. We address the dominant systematic uncertainty of the previous analysis through a depth fiducialization designed to reject surface backgrounds on the CCDs. The measured bulk ionization spectrum confirms the presence of an excess population of low-energy events in the CCD target with characteristic rate of ∼7 events per kg-day and electron-equivalent energies of ∼80 eV, whose origin remains unknown.
- Published
- 2024